Nearly every surgical procedure employs electrosurgical techniques to diminish both blood loss and operating time. Small blood vessels are sealed by heat, obviating the need to meticulously and laboriously tie off by hand each blood vessel.
In using an electrosurgical pencil, either for coagulation of blood or for cutting through tissue, a large volume of smoke is generated. This smoke contains aerosolized and vaporized organic material, carbon particles, steam, and viable viral particles. This smoke raises concerns about exposure and transmission through the respiratory tract by inhalation of viable human papillomavirus, HIV (AIDS), Hepatitis B, and non-A, non-B hepatitis viral particles in the electrocautery smoke plume. Operating room face masks and face shields are, at best, only marginally protective. There is also concern that the vaporized organic material and carbon particles may be carcinogenic. Finally, the odor of burning flesh is offensive to those exposed to it. These problems have led to a long-felt universal desire for a solution to this occupational environmental health hazard that does not interfere with the necessary and established functions of each member of the operating team, that is inexpensive, effective, easy to set up and use, has no additional moving parts to slide or manipulate, and is disposable.
The usual operating team consists of a scrub nurse or technician, who passes instruments and sutures, and occasionally holds retractors and suctions blood; a surgeon, who performs the surgical procedure; and often, a surgical assistant or assistant surgeon, who holds retractors, cuts sutures, suctions blood, and otherwise assists the surgeon by providing an extra pair of hands. In addition, there is usually an anesthesiologist or anesthetist close to the operating field. When large volumes of smoke are generated by the electrosurgical pencil, either the scrub nurse or the surgical assistant will make an attempt to suction the smoke with a Yankaur or other suction instrument if their hands are free. The surgeon generally has the electrosurgical pencil in one hand, and a retractor or sponge in the other. All of the suction instruments in common usage have small apertures designed for liquids, and are relatively ineffective for suctioning smoke. In addition, because placing these suction instruments near the point of smoke generation blocks the surgeon's field of view, the smoke has usually had a chance to disperse widely, so that little of it reaches the aperture of the suction instrument. And finally, personnel usually do not have their hands free to attempt continuous suction of the smoke. This results in a heavy exposure to smoke of the entire surgical team.
Heretofore, attempts to solve the problem of effective smoke elimination have been expensive and/or cumbersome, and most often, mentioned as an afterthought to the function of suctioning blood and other liquids. The infectious and carcinogenic potential of smoke generated from an electrocautery instrument was not always appreciated, and prior art usually mentioned clearing smoke only to give the surgeon a clear field of vision, which, in fact, is rarely a problem. None of the prior art has been directed at eliminating the hazard of smoke inhalation by utilizing a design which, while adding no moving parts to a hand-switchable instrument, effectively, simultaneously, and continuously traps smoke in a 360.degree. arc around the point where it is generated at the electrode blade tip before the smoke diffuses while leaving the surgeon's view unobstructed.
None of the prior art comprises a transparent addition to the functionality of the electrosurgical pencil while maintaining its hand-controlled cutting and cautery functions and its interchangeable bits. None of the prior art has the qualities of being inexpensive and disposable, and of requiring no extra training, setup time or packaging. Also, most prior art devices utilize a single hollow tube for both cautery and suction, which significantly diminishes the prior art's utility as an electrosurgical instrument, making the prior art unsuitable for cutting and unable to accept interchangeable bits, and, most importantly, unable to trap smoke effectively because the smoke disperses laterally away from the tube walls as it is generated.
U.S. Pat. No. 2,888,928 is a design for an instrument with a hollow shaft for suction and cautery. The shaft renders it unsuitable for cutting. It cannot accept interchangeable standard bits, is expensive to manufacture and clean, and it is not meant to be disposable. In addition, its hollow shaft design renders it marginally effective for trapping smoke.
U.S. Pat. No. 4,307,720 is an electrocautery instrument with a suction tube associated with and located in close proximity to a retractable cauterizing blade. While this device may have some usefulness, it is relatively expensive and awkward to use. The suction port consists of a single small aperture located below the electrode blade, making it unable to trap smoke in anything close to the 360.degree. arc around the electrode blade that is necessary for it to be effective.
U.S. Pat. No. 3,906,955 is an electrocautery instrument with a manually retractable suction tube located beneath and in close proximity to a cauterizing blade. Its moving parts make it expensive to manufacture and cumbersome to operate. In addition, the position of the suction port below the electrode blade make it poorly suited for suctioning smoke. The retractable suction tube is meant to extend out to the cauterized area for suctioning blood and tissue debris before or after cauterization, but not during.
U.S. Pat. Nos. 2,808,833, 3,825,004, 3,828,780, 3,902,494, 3,974,833 and 4,347,842 are combined electrocoagulator-suction instruments utilizing a hollow shaft for suctioning blood and other liquids from the operating field and for cauterizing. They have no utility for evacuating smoke from the operating field, nor are they useful for cutting through tissue.
U.S. Pat. No. 4,865,049 is a smoke-eliminating shield with no electrosurgical function. It does not prevent smoke from dispersing in all directions before attempting to trap it. It also requires additional packaging and setup time, which at an average of $15 per minute for operating room time, becomes expensive for the patient.
U.S. Pat. No. 4,683,884 is conceived as a noise attenuating smokeless surgical device. It specifies an electric cable running through the wall of the tubular housing, rather than in an axial line through the center of the device, thereby offsetting the blade where it would be both difficult to see and awkward to use. There is no allowance for electrical hand switches, nor is the means of attaching the blade to the electric cable in the suction housing specified. The position of the blade relative to the suction intake would cause the tubular housing to obscure the blade tip from the surgeon's vision. Although the design may function as a noise-suppression device, it has questionable utility as an electrosurgical instrument, and none as a hand switchable instrument. In addition, Hatfield's invention is designed for noise suppression, which is not in the area of the present invention.
U.S. Pat. No. 4,719,914 is essentially a hollow tube with an opening at one end to which a vacuum may be applied, and with a tapered nose portion at the other end through which an electrocauterizing blade protrudes. This nose portion has a plurality of openings for withdrawing smoke. Application of the vacuum through the nose portion openings is achieved by moving a sliding sleeve along the body of the instrument so that it extends over the openings in the nose portion and surrounds the cauterizing blade. Because this design is comprised of a tube sliding over a tube, the outer tube, which forms the extensible hood, must have walls that are either parallel to each other, or flare out. If the walls of the hood tapered inward, than it would not be able to retract back onto the body of the instrument. In designing and testing the present invention, early prototypes employed a design which duplicated Johnson's hood in the extended position with parallel sides. Tests of this configuration conclusively demonstrated that for the instrument to effectively aspirate smoke generated at the electrocautery blade tip, the aperture of the hood had to be so close to the tip of the blade that, when held in a position that would actually be used on the surgical field, the extensible sleeve obscured the tip of the blade, which is unacceptable.
U.S. Pat. No. 4,850,352 is a continuation-in-part of U.S. Pat. No. 4,719,914 cited above. It applies the same design of an extensible sleeve to a laser surgical instrument. The objections cited for the co-patent above apply equally. In addition, a laser is aimed indirectly through an optical system such as an operating microscope. An electrosurgical blade is guided under the direct vision of the surgeon. A laser also does not have electrical switches that can come in contact with conductive liquids. The two instruments, therefore, cannot be construed as being interchangeable because they have substantially different requirements for intrinsic electrical safety and for the safe placement of a beam versus a blade.